Measuring compliance with the 15-minute city concept: State-of-the-art, major components and further requirements

Triggered by the COVID-19 crisis, the 15-min city concept has emerged as a new model of city vision. This increasingly popular urban planning paradigm brings the idea of living locally at the forefront of city planning, aiming to alleviate the intense urban challenges. Although the 15-min city concept may hold a paradigm changing potential for the future of urban and transport planning, its implementation should be supported by a comprehensive methodology for assessing cities' compliance with the concept requirements, which in turn requires a thorough understanding of the concept's core elements and principles. While previous research has contributed greatly to the literature of measuring cities' performance from a 15-min city perspective, some theoretical and, in particular, methodological questions remain open. To this end, the current paper seeks to shed light on these issues, through examining the key components, determining the state-of-the-art and the predominant practice, identifying the gaps, and providing recommendations for a more holistic compliance assessment. The major gaps were found to be related to the methodological approaches used, with the different concept dimensions being treated in a fragmentary manner. The recommendations provided could further enhance the performance evaluation process, towards the development of accessible and well-connected urban neighborhoods.